In many fields of endeavor, it may be useful to characterize a parameter relating to an earth formation, such as parameters relating to one or more fluids of the earth formation. For example, in exploration, development, and monitoring related to hydrocarbon production, it is important to make accurate measurements of geologic formations. The geologic formations below the surface of the earth may contain reservoirs of oil and gas or underground bodies of water. The geologic formations may include formation layers and various structures. In a quest for oil and gas, it is important to know about the location and composition of the formation layers and the various structures. In particular, it is important to know about the geologic formations with a high degree of accuracy so that resources are not wasted. In some applications it may also be useful to monitor fluids injected into the formation to increase production of hydrocarbons. The present disclosure addresses the need to characterize gravity measurements to estimate the behavior of injected fluids.